It has been known that aeration of fluids in standing liquid waste ponds, collection basins, and the like serves to introduce fresh oxygen into the liquid, thereby encouraging aerobic activity. Aerobic bacteria can thus function within the oxygenated fluid to break down organic materials. Otherwise, a stagnant pond will function substantially only with anaerobic breakdown of sludge. Anaerobic activity results in the release of gasses that produce an extremely noxious smell about the vicinity of the pond. Further, anaerobic activity by itself is an inefficient process for breaking down organic solids. Aerobic bacteria, on the other hand work 4 to 6 times faster than anaerobic bacteria at normal liquid temperatures of 50.degree. Fahrenheit. Anaerobic bacteria work best at liquid temperatures of 100.degree. Fahrenheit. Plus, the gasses normally vented to the atmosphere during anaerobic breakdown are substantially eliminated during aerobic activity.
In an attempted solution to the problem of introducing effective aerobic breakdown, aerators have been developed for placement on pond surfaces to force oxygen into the pond fluids. Some of the surface aeration equipment include impellers that are used to circulate the liquids near the pond surface. The circulating fluids will be exposed to free air at the pond surface and aerobic activity is thereby increased. More sophisticated systems force air into the pond fluids, again at or near the surface. While this further increases oxygen content, only the upper strata of the fluid material is affected and anaerobic activity still occurs in the major portions of the lower levels of the pond including the sludge at the bottom.
It is an objective of the present invention to provide a liquid circulation system that is useful to encourage aerobic bacterial decomposition to a greater depth than presently known forms of surface aeration systems.
The above and further objects and advantages will become apparent from the following description which, taken with the accompanying drawings, exemplify a preferred mode of the present invention.